Best available copy



E. A. WATSON.

DYNAMO ELECTRIC MACHINE.

APPLICA'HON min ml. 3|. 1917.

1,319,543. Patented Oct. 21,1919.

Fig.3

mas/v roe imam Ansley Wald-022 A TTOQNEYJ UNITED STATES PATENT OFFICE.

ERNEST ANSLEY WATSON, 0F COVENTRY, ENGLAND, ASSIGNOR, BY MESNE ASSIGN-MEN'I'S, TO THE C. L. I. MANUFACTURING COMPANY LIMITED, 0F BIRMINGHAM,

ENGLAND.

DYNAMO-ELECTRIC MACHINE.

Specification of Letters Patent.

Patented Oct. 21, 1919.

Application filed January 31, 1917. Serial No. 145,697.

To all whom it may concern:

Be it known that I, ERNEST ANSLEY WAT- SON, a subject of the King ofGreat Britain and Ireland, residing at Victoria Works West Orchard,Coventry, in the county of Warwick, England, have invented certain newand useful Improvements Relating to Dynamo-Electric Machines, of whichthe following is a specification,

This invention has for its object to construct an improveddynamo-electric machine for the generation of low tension current forlighting or lighting and starting purposes, and high tension current forignition purposes, on motor road and other vehicles driven by internalcombustion engines, the machine being of the type in which there arecombined with the generator field winding, an additional windlng servingas a secondary of a high tension ignition system, and a contactmechanism rotating synchronously with the engine for intermittentlymaking and breaking the circuit of the field winding.

The invention comprises the provision in the machine of a magnetic shuntor leakage circuit common to the flux of the wound pole and the opposingflux associated with the armature.

Referring to the accompanying sheet of explanatory drawings Figure 1 isa cross section; and

Fig. 2 a longitudinal section showing diagrammatically a dynamoconstructed in accordance with this invention;

Fig. 3 is a dia am; of connections.

In carrying t e invention into effect as shown, the ordinary fieldwinding a of a low tension generator suitable for lighting or li htingand starting purposes is surrounded y another winding 6 which serves asa secondary of a high tension ignition system. Any suitable mechanismsuch as that ordinarily employed on magnetos is provided forinterrupting the field winding, and such mechanism is rotatedsynchronously with the en ine. The arrangement shown consists 0% a fixedcontact 0 and a movable contact d. The latter is mounted on a spring arm(3 actuated by a cam f on a wheel 9 driven by a pinion h on the shaft 2'of the armature 7'.

For the production of a spark, a com ara tively small flux changesuflices, provi ed it occurs with sufficient rapidity. The com binationabove described would not result in an efficient ignition apparatusbecause the inductance associated with the armature would tend to resista rapid change of flux in the field winding. To avoid this it isnecessary to produce a magnetic path which is associated with the fieldwinding only and is independent of the armature. Such a path is obtainedby the arrangement of an air gap or leakage path or shunt on each sideof the pole piece In and the adjacent part of the frame Z. While thesepaths are not narrow enough to seriously interfere with the flux fromthe core m to the armature, they do insure a definite amount of fluxpassing from the pole tips to the frame. There are thus two paths forthe core flux, one which includes the armature through which the greaterpart of the core flux passes and a second across the leakage paths orshunts which takes a relatively small amount of the flux. The lattercircuit is independent of the armature and consequently the fluxassociated with it can change with the necessary rapidity to produoe aspark in the secondary or high tension current circuit when the currentin the field winding is interrupted.

Further in ordinary automobile current generators the demagnetizingmagneto-motive-force associated with the armature is usuallyconsiderable. The leakage flux due to this magneto-motive-force, or someof it, also crosses the above mentioned leakage paths but does not enterthe core m when the winding a is energized. When the winding a isinterrupted, the demagnetizing magneto-motive-force tends to reverse theflux through the main core m and hence increases the rapidity of fallingof the main flux and therefore assists in the process of flux changenecessary for the spark.

In the arrangement shown the core m is laminated and formed integrallywith a laminated portion Z of the frame. This portion is removable andis attached to the solid main portion Z in any convenient man-- ner. Thevole piece it is secured to the main portion of the frame by cross boltsn of non-magnetic material such as brass and the leakagepaths are filledwith blocks 0 of nonmagnetic material such as brass, these also beingsecured by the bolts a.

Any suitable cut-in and cut-out device is arranged at p to preventdischarge of the battery through the armature j, and a switch isprovided at r. In the diagram at Fig. 3 the battery is indicated by 8,the sparking plug by t and the lamps by u. A condenser "u is provided tosuppress sparkin at the interrupter of the field winding. 1* igh tensioncurrent taken from the winding 11 by a terminal as w. Any mnvcuientadditional means may be employed in the generator for producingautomatic regulation of the current or voltage. Obviously two or morefield windings may be use without departing from the invention. when theenerator is required to operate as a motor for engine starting purposesany suitable provision is made for temporarily convert-- ing thegenerator into a series motor. For ignition in multi-cylin-der en ines adistributor is combined with the igh tension system of the machine.

The invention is not limited to any particular mechanical details asthese may be varied to meet different requirements.

Having thus described my invention What I claim as new and desire tosecure by Letters Patent is I 1. In dynamo electric machines, thecombination of an armature, a magnetic frame consisting in art of asolid main portion and a detacha le laminated portion, a laminated coreformed integrally with said lami- Ila-ted orti'on of the frame, a polepiece secured o the main portion of t e frame and abutting against thesaid core, said pole piece being spaced from said frame, to provide amagnetic shunt between the ends of the pole piece and the adjacent partsof the a field winding acting as a primary winding and a secondarywinding on the core, an interrupter in the primary Winding, and means"For actuating the interrupter from the armature, substantially asdescribed.

2. In a dynamo electric machine, a magnetic frame, an armature disposedwithin the frame at one end thereof, a core carried by the frame at theopposite end thereof, a pole piece carried by the core, said pole piecebeing spaced from the frame to pro vide a magnetic shunt, nonana 'neticblocks dis osed in the space between t 1e pole piece ant the frame, andsecuring means arranged lo pass through the frame, the blocks and thepole piece for holding the parts together.

In a dynamo electric machine, a magnetic frame, an armature disposedwithin. the frame at one end thereof, a core carried by the frame at theopposite end there of, a pole piece carried by the core said pole piecebeing spaced from the frame to provide a magnetic shunt, non-magneticblocks dis osed in the space between the pole piece an the frame,securing means arranged to pass throu h the frame the blocks and thepole piece or holding t e parts together, a primary field Winding on thecore, a secondary field Winding superposed on said primary winding, aninterrupter in the primary Winding, and means for actuating theinterrupter from the armature.

In. testimony whereof I have signed my name/co this s ecification.

ERN ST ANSLEY WATSON.

frame copier of this patent may be obtafnel hifl'we cents each, byaddressing the Commissioner 0? Patents, Washington, D. C.

